Veja o excerto tirado da Wikipedia:
Open Cobalt is a free and open source software platform for constructing, accessing, and sharing virtual world both on local area networks or across the Internet, without any requirement for centralized servers.
The technology makes it easy to create deeply collaborative and hyperlinked multi-user virtual workspaces, virtual exhibit spaces, and game-based learning and training environments that run on all major software operating systems. By using a peer-based messaging protocol to reduce reliance on server infrastructures for support of basic in world interactions across many participants, Open Cobalt makes it possible for people to hyperlink their virtual worlds via 3D portals to form a large distributed network of interconnected collaboration spaces. It also makes it possible for schools and other organizations to freely set up their own networks of public and private 3D virtual workspaces that feature integrated web browsing, voice chat,text chat and access to remote desktop applications and services.